1. Field of the Invention
The system of the present invention relates to oil and gas production. More particularly the present invention relates to a system for supporting a well head conductor and/or caisson extending from the surface of a body water, such as the Gulf of Mexico, in vertical relationship for withstanding wave action and the like in the body of water.
2. General Background
In offshore oil and gas production, a well head conductor would comprise a length of pipe that is driven around the drill line that protects the drill line. The drill line would carry the hydrocarbon product up to the well head or the "Christmas tree" for allowing the products to be diverted to vessels or to shore. The drill line is run inside the well conductor, which is driven over the drill line to protect it against the elements. The problem that is confronted is wave-action and other interferences such as boats or the like. The conductor must be secured because although the conductor is of sufficient size, it could be knocked over, or tipped with those various elements in it. Therefore, it must be protected and given some sort of support. Support may take the form of a caisson (a minimal support) or another support structure as in the past, and in deep water, normally what is provided is a four legged jacket with the legs extending outward at an angle in order to give it support so that production equipment can be placed on it. However, within the last five to ten years, operators of oil companies have moved away from expensive steel structures with a jacket and a deck, and have attempted to provide caisson installations for supporting the conductor pipe about the caissons. The problem to overcome, therefore, is placement of a support structure onto a single pipe such as a conductor and/or caisson extending out of the water, without damaging the structure or placing support on the conductor and/or caisson which should not be placed thereupon.
In the present state of the art, there is a system called the "Moss One System" which utilizes clamps clamped around the caisson which includes brackets which extend outward therefrom. At that point pilings are driven on a batter or a slight degree into the mud line and below the mud line at the bottom of the water. The structure is referred to as K-system structure in that it appears like an inverted K on both structures. The problem confronted in this type of structure, is that once it is installed there is only approximately 270.degree. of accessibility to the caisson, due to the large pipe extending therefrom. If, therefore, a support deck is to be secured on the top of the structure, the support deck must clamp to the caisson and into the pilings that are projecting up to the water line. When this is done, the caisson becomes a third leg of the structure supporting a third of any of the forces that are being placed on it. Therefore it is strictly another clamp to the caisson. The system would also provide the unnecessary additional weight on the caisson.
An additional type of arrangement is entitled a "Sea Horse". The sea horse apparatus secures to the caisson by clamps and go from the mud line up above the water line. The clamp is bolted together so there is an enormous amount of diving time involved in the setting up of the system. The base of the sea horse clamp is approximately forty by forty feet square where piling are driven through the "cans" that are accessible into the mud line. The problem confronted is that a jack-up type vessel cannot get within twenty-five feet of the caisson without the vessel pads contacting the large structure sitting on the sea floor, and this arrangement causes in effect the requirement of a larger vessel so that lifting requirements can be met.
A third system which is utilized as a conductor anchoring system is a tension anchoring system. This particular system comprises clamp and a sheeve clamp. Piles are driven below the mud line, to secure a cable that it is attached to it through the shift clamp which allows movement up to the end clamp which is utilized to pull the tension on the cable. Once it is in place, there are three cables extending from the sea bed to ten feet below the water line which causes inaccessibility from jack-up type vessels coming in if they cannot see the sea lines underneath the water line. This is not a permanent structure, since it cannot take any significant weight since all of the weight would be going into the conductor and/or caisson.
There are several patents in the art which address offshore structures and the support of the those structures, the most pertinent being as follows:
______________________________________ PATENT NO. INVENTOR TITLE ______________________________________ SU 1,013,573 "Jig For Constructing Pile Base" 1,563,107 (U.K.) Victor Sutton "Piling" 2,200,937 (U.K.) Anton Coppens "Offshore Tower Structure" 3,389,562 Mott et al. "Salvageable Multi-Well Offshore Well Protector Platform" 3,670,507 Mott et al. "Marine Drilling Structure With Curved Drill Conductor" 3,991,581 Kolb "Method and Apparatus For Handling Piling And Anchoring An Offshore Tower" 4,740,107 Casbarian et al. "Method And Apparatus For Protecting A Shallow-Water Well" 4,793,739 Hasle et al. "Offshore Structure" 8,401,934 Marcon Marine "Structure-Supported (Netherlands) Leg From Sea Bed" ______________________________________